Butler was last seen talking to her boyfriend, Jose Angel Rodriguez-Cruz, at her home in the 5800 block of 4th Street northwest in Washington D.C. at 9:48 p.m. on February 12, 2009. The following day she sent two emails, one to her employer and one to a relative. She has never been heard from again.

Butler was very concerned about personal safety and her residence has a sophisticated security system with an alarm, motion-activated floodlights and surveillance cameras positioned at all the exits. She kept the home in a very neat, clean condition. When her brother checked the house, he found the sheets from her bed were missing, the bed's comforter was on a settee in the bedroom, some real estate files were on the floor in her home office, and blinds on one of the windows in the second floor dining room were raised. It would be uncharacteristic of Butler to leave the blinds up, as she didn't want neighbors to see into her home. That particular window was the only one in the house that was unlocked. The door alarm was turned off, and her family says she always set it before she left home. Authorities searched her home after her disappearance and found no evidence of foul play. She left behind her vehicles, a gray Mercedes-Benz and a gold Jaguar, but her purse, credit card, driver's license and keys disappeared with her.

Rodriguez-Cruz stated Butler broke up with him on the evening of February 13. They met through an internet dating website and had been together for five months. He said the split was amicable, but sudden, and he didn't understand why Butler wanted to the end the relationship. The surveillance videos show him leaving the house at 11:30 p.m. on February 13. He was filmed coming in and out of Butler's house three times in the days following her disappearance. He says he was removing his belongings from the home and dropping off other items; this would be consistent with the films, which show him carrying bags away. The films don't show Butler leaving the house; the last time she was filmed was on the evening of February 12, when she went out to get her mail, then came back inside.

Rodriguez-Cruz initially cooperated with the investigation and allowed the police to question him and search his home. Authorities have focused on him as a possible suspect. They impounded his car and some other belongings and questioned him aggressively, but they haven't found any evidence to implicate him. He agreed to take a polygraph, but then refused and walked out just before the exam was to begin. Following that incident, he ceased cooperating, saying he felt he was being railroaded by overzealous police officers. Rodriguez-Cruz has had some minor run-ins with the law, but he has no serious criminal record and has never served time in jail. Butler's relatives, including a nephew who lived with her off and on during the relationship, said she and Rodriguez-Cruz seemed happy and got along well, with only minor arguments. They said they had no idea she was planning to break up with him.

Butler has a bachelor's degree in information technology and a master's degree in public administration from American University. Her single, brief marriage ended amicably in the 1990s. At the time of her disappearance, she was employed as a computer systems analyst with the Office of Enforcement and Compliance Assurance at the Environmental Protection Agency (EPA). She earned a six-figure salary with the EPA, and supplemented her income with real estate investments. Butler was stressed over financial problems at the time of her disappearance; her investments had declined in value due to the bad economy. She kept in close contact with her family and had a regular routine and an orderly life, and it's uncharacteristic of her to leave without warning. Her case remains unsolved.